- The single thin blue line shows David Mundell's current constituency
- The purple highlighted area shows David Mundell's proposed new constituency
South of Scotland Tory MP David Mundell's constituency is set for radical change under plans unveiled today by the Boundary Commission.
Mr Mundell's seat of Dumfriesshire, Clydesdale and Tweeddale will lose Peebles and Innerleithen but gain an area of South Lanarkshire including the towns of Forth and Lanark.
The new Westminster constituency, called Clydesdale and Eskdale, will stretch more than 70 miles from Gretna near the border with England to Carluke, under eight miles south-east of Motherwell.
Mr Mundell, who is also Secretary of State for Scotland, told me that he welcomed the work of the Boundary Commission but would "reflect" on whether the plans proposed a "coherent new constituency".
The proposed changes leave the other two existing seats in the south of Scotland largely unchanged.
Innerleithen moves into the Berwickshire, Roxburgh and Selkirk constituency, currently held by the SNP's Calum Kerr.
- The thin blue line shows the current constituency boundaries
- The green highlighted area shows how the new Berwickshire, Roxburgh and Selkirk constituency would look
- The blue highlighted area shows how a new Midlothian and Peebles seat would look
There are only small changes to the Dumfries and Galloway constituency, held by the Nationalist's Richard Arkless, losing the town of Moniave to the new Clydesdale seat.
- The thin blue line shows the current constituency boundary
- The green highlighted area shows the proposed new Dumfries and Galloway constituency, without the town of Moniave
A new Midlothian and Peebles seat shakes things up, taking in an area from the southern outskirts of Edinburgh down to the countryside just north of Moffat.
- The blue highlighted area shows a proposed new constituency for the south of Scotland, called Midlothian and Peebles
The proposals from the Boundary Commission for Scotland are part of a move to cut the number of MPs at Westminster from 650 to 600.
In Scotland the number will be reduced from 59 to 53.
The Commission was given the task of making sure constituencies were all roughly the same size in terms of the numbers of people who live in them - within five percent of a quota, 74,769.2 to be precise.
Each constituency was not to exceed 13,000 square kilometres.
The proposals are just that and the Commission is stressing that it is open to the public as well as the political parties to make suggestions of changes, of boundary and constituency names.
Political parties and the public will be treated equally, the Commission says.
The final say on the plans will lie with the Commons and the Lords with Labour threatening to reject them as across the UK it is set to lose out to the Tories.
As the plans were released under an embargo yesterday all the political parties were looking at what effect it would have on them.
According to Scotland's foremost electoral academic, Professor John Curtice of Strathclyde University, if last year's general election were replicated the SNP would lose four seats across Scotland, the Conservatives one, and Labour one.
That one Conservative seat would be Mr Mundell's under the new boundaries as he would inherit areas in the Clydesdale area which are not naturally Tory voting.
Mr Mundell held his seat at the last UK election by 798 votes over the SNP. Prof Curtice told me:
Mr Kerr won his seat by an even smaller majority of 328 over the Tories.
Mr Arkless had a comfortable majority of 6,514 over the Tories.
Mr Mundell - speaking in his party not government capacity - told me that he supported the idea of cutting the number of MPs.
But he added:
One of the most notable proposals in the rest of Scotland is that the current Edinburgh South constituency - Labour's only seat north of the Border - would disappear.
Scottish Labour’s Westminster spokesperson Ian Murray, who holds the seat, said:
Both Labour and the SNP will be drawing attention to what they say are the double standards of the Conservatives in creating more costly members of the House of Lords while claiming to want to save money with fewer MPs.
Mr Kerr told me he was looking forward the opportunity to represent additional communities in the Scottish Borders.
But he added that with scrutiny of the UK government's Brexit plans the priority for the Commons he did not believe now was the time to reduce the overall number of MPs.
Mr Kerr added: